The prevalence of obesity has grown in an alarming rate in the past 20 years. Based on an estimate in 2004, in the US alone, 66.3% of adults are either overweight or obese, and 32.2% of adults are classified as obese (Cynthia L. Ogden et al., JAMA 2006 Apr. 5; 295:1549-1555). Both genetic and environmental factors have been shown to cause positive energy balance and obesity. Obesity by itself is only a part of problems. Many other chronic diseases such as type 2 diabetes, certain cancers and cardiovascular diseases are common co-morbidities of obesity. Collectively, all the obesity associated medical issues put a tremendous amounts of pressure on health care systems in many countries.
Drug treatments for obesity are available but not very effective and with undesirable side-effects. Still more drugs are under development to improve the safety, efficacy of the medications and convenience to use them by patients. To date, all anti-obesity treatments are designed to alter the internal metabolism of patients. Most of these drugs are required to be absorbed and delivered to target organs through blood stream for their efficacy. Safety concerns of such a treatment strategy cannot be ignored.
Novel treatment strategies of obesity and type 2 diabetes focussing on targets outside of human tissues is greatly desirable because the active agents are not required to enter our body, and the safety of the treatments can be improved significantly.
Recent research has shown that gut bacteria play a role in the development of obesity and related metabolic disorders such as diabetes (Kristina Harris, et al., Journal of Obesity 2012; 2012:879151; doi:10.1155/2012/879151). Human beings are superorganisms with a body composed of millions of human cells while many more bacteria live, e.g., in the colon. It has been estimated that more than 1013 to 1014 bacteria are alive in a healthy human intestine. Intestinal bacteria can be separated into 2 major divisions, Firmicutes and Bacteriodetes (Steven R. Gill, et al., Science 2006 Jun. 2; 312:1355-1359; Peter J. Turnbaugh, et al., Nature 2006 Dec. 21; 444:1027-131). Together, they represent at least 90% of total bacterial population in the gut. The presence of the gut bacteria is a part of normal human physiology and is important for the development of gut functions (Hooper L V et al., Science. 2001 Feb. 2; 291(5505):881-4; Stappenbeck T S, et al., Proc Natl Acad Sci USA. 2002 Nov. 26; 99(24):15451-5), maturation of the immune system (Mazmanian S K, et al., Cell. 2005 Jul. 15; 122(1):107-18), harvesting energy from dietary carbohydrates (Peter J. Turnbaugh, et al., Nature 2006 Dec. 21; 444:1027-131), harvesting essential vitamins (Backhed F, et al., Science. 2005 Mar. 25; 307(5717):1915-20) and metabolizing environmental chemicals in the gut (Nicholson J K, et al., Nat Rev Microbiol. 2005 May; 3(5):431-8). Recent studies further suggested that gut bacteria may be involved in fat storage (Backhed F, et al., Proc Natl Acad Sci USA. 2004 Nov. 2; 101(44):15718-23).
WO 2006/019222 discloses Lactobacillus rhamnosus strain PL60 KCCM-10654P with a body-fat reducing activity that overproduces t10c12-octadecadienoic acid.
U.S. Pat. No. 7,001,756 and CN1670183 provide an isolated microorganism strain Lactobacillus rhamnosus GM-020 which is found to be effective in treating obesity.
WO 2009/0218424 describes a composition comprising Lactobacillus rhamnosus strain CGMCC 1.3724 or NCC4007 which is useful for supporting weight loss or weight management.
WO 2009/024429 describes a similar composition comprising Lactobacillus rhamnosus strain CGMCC 1.3724 or NCC4007 for the use in treating or preventing metabolic disorders. The composition was shown to modify the amount of Proteobacteria in the gut. Optimum results were achieved when the ratio of Proteobacteria to Bacteriodetes was reduced. At the same time, the ratio of Proteobacteria to Firmicutes and/or the ratio of Bacteriodetes to Firmicutes may be increased.
However, further elucidation of the relationship between gut microbiota and body weight is required in order to provide a solid basis for the development of effective and safe strategies for body weight management.
It was one thus an object of the present invention to improve the management of body weight and, in this context, the treatment of obesity and overweight by modulating the population of gut bacteria.